This invention relates to a safety device and more particularly, but not exclusively, to safety devices for use on large structures, such as aircraft wings, ships, storage silos, tanks, etc., to enable safe inspection or maintenance of such structures.
According to a first aspect of the present invention there is provided a safety device comprising a vacuum anchor having a sealing member for contact with a surface, a support portion attached to the sealing member and means for producing a vacuum below the sealing member such that the safety device is held with respect to the surface by suction, the support portion having a boss adapted to receive additional equipment.
Preferably the sealing member is substantially circular and the boss is centrally located.
It is a preferred feature that the boss has a central, axially extending, blind bore to allow insertion of a mating part of the additional equipment.
Another preferred feature is that the support portion includes a radially extending arm which is rotatably mounted on the boss and which has one or more holes for attachment of a safety line. The arm may have a collar portion which is disposed around the boss and which is retained thereon by means of a removable retaining plate.
Conveniently, the sealing member comprises a base plate to which the boss is attached and a sealing ring secured with respect to the base plate and extending about the periphery of the base plate. The sealing ring may be clamped with respect to the base plate by means of a circular clamping ring. In some embodiments, the sealing ring has a pair of concentric main sealing lips and an additional secondary peripheral sealing lip which is radially outwardly disposed from the main sealing lips. Preferably, the secondary sealing lip has an outward facing surface which has at least one and preferably two peripheral reinforcing ribs.
The sealing ring is formed from rubber or synthetic rubber, preferably from nitrile rubberxe2x80x94acrylonitrile butadiene rubber (NBR).
Ideally, the vacuum means comprises a vacuum reservoir which is adapted to be connected to a vacuum via a non-return valve and which communicates with the sealing member via a manual control valve and normally the vacuum means includes a vacuum gauge.
Preferably, the support portion incorporates a rigid cover to protect the vacuum means which is disposed between the cover and the sealing member. Also, the additional equipment may include tools, ladders, safety barriers, handrails.
According to a second aspect of the present invention, there is provided a safety system comprising a plurality of safety devices as described above and one or more bar means extending therebetween.
In some embodiments, the or each bar means comprising a tube hingedly connected at each end to a coupling which cooperates with the boss of a safety device.
In further embodiments, the bar means comprises a safety barrier having an upright member at each end, each upright member cooperating with the boss of a safety device and having at least one bracket for receiving one of the couplings which are hingedly connected to the tube. Conveniently, a bracing foot is adjustably secured at the radially outermost end of the radially extending arm of each safety device.
According to a third aspect of the present invention, there is provided a safety device comprising a vacuum anchor having a sealing member for contact with a surface, a support portion attached to the sealing member and means for producing a vacuum below the sealing member such that the safety device is held with respect to the surface by suction. The sealing member has a sealing ring which has a pair of concentric main sealing lips and an additional secondary sealing lip outwardly disposed therefrom, the secondary sealing lip having on an outward facing surface and at least one and preferably two peripheral reinforcing ribs. Normally, the sealing lips are generally triangular in section when relaxed with the secondary lip projecting axially further than the main lips for providing a pre-seal.